Build atmosphere aided texture control in additively manufactured FeCrAl steel by laser powder bed fusion

Abstract

Through properly selecting the process atmosphere, involving pure argon gas (Ar) and nitrogen gas (N2), we have achieved the in-situ texture control of laser powder bed fusion (LPBF)-manufactured FeCrAl parts with fixed process parameters. The results, from crystallographic orientation analysis, indicate that a single crystalline-like microstructure is developed under the N2 process atmosphere while printing under the common Ar case results in a chessboard-like microstructure composed of strong fiber texture with 〈111〉 along the Z-axis (building direction) and cube texture with 〈001〉 parallel to X-, Y-, and Z-axes. The texture control mechanism under different process atmospheres has been elucidated by extracting the corresponding molten pool morphology information, that is flat molten pool for the N2 process atmosphere but keyhole one for the Ar case. The current findings demonstrate the feasibility of utilizing the process atmosphere of additive manufacturing to manipulate the crystallographic texture of metals.